Saturday, October 25, 2014

In the Devils Punchbowl area, the Astoria Formation is shot through with numerous, nearly vertical faults with small offsets- generally, just a couple inches. They're not obvious at the above photo scale, but more so in the full-size image. For a fracture to be declared a fault (as opposed to a joint), one must be able to show there was offset parallel to the plane of the fracture. Even in the full-size photo, many of the cracks in this view are questionable as faults, but it's much easier to see the small offsets when you can get your face up against the outcrop. Obviously, though, that's not going to happen here.